xkeyboard-config before 2.5 in X.Org before 7.6 enables certain XKB debugging functions by default, which allows physically proximate attackers to bypass an X screen lock via keyboard combinations that break the input grab.

Use-after-free vulnerability in the doImageText function in dix/dixfonts.c in the xorg-server module before 1.14.4 in X.Org X11 allows remote authenticated users to cause a denial of service (daemon crash) or possibly execute arbitrary code via a crafted ImageText request that triggers memory-allocation failure.

Integer overflow in the ProcRenderAddGlyphs function in the Render extension for X.Org 6.8.2, 6.9.0, 7.0, and 7.1, and XFree86 X server, allows local users to execute arbitrary code via a crafted X protocol request that triggers memory corruption during processing of glyph management data structures.

Integer overflow in the ProcDbeGetVisualInfo function in the DBE extension for X.Org 6.8.2, 6.9.0, 7.0, and 7.1, and XFree86 X server, allows local users to execute arbitrary code via a crafted X protocol request that triggers memory corruption during processing of unspecified data structures.

Integer overflow in the ProcDbeSwapBuffers function in the DBE extension for X.Org 6.8.2, 6.9.0, 7.0, and 7.1, and XFree86 X server, allows local users to execute arbitrary code via a crafted X protocol request that triggers memory corruption during processing of unspecified data structures.

Integer overflow in the CIDAFM function in X.Org 6.8.2 and XFree86 X server allows local users to execute arbitrary code via crafted Adobe Font Metrics (AFM) files with a modified number of character metrics (StartCharMetrics), which leads to a heap-based buffer overflow.

Integer overflow in the scan_cidfont function in X.Org 6.8.2 and XFree86 X server allows local users to execute arbitrary code via crafted (1) CMap and (2) CIDFont font data with modified item counts in the (a) begincodespacerange, (b) cidrange, and (c) notdefrange sections.